Eerie, desolate wastes in old novels, salt marshes are still seen as flat, grey and inhospitable landscapes today. Rainforests, meadows, oceans and even peatlands have their celebrity champions. But now there is someone to speak up for the magnificence of the tidal marsh: Sophie Hunter, theatre-maker and opera director, hopes her new performance installation will make us take more care of these crucial, carbon-sequestering coastal guardians. A salt marsh doesn’t attract attention, perhaps because not much seems to happen in these expanses of grass and creek. “And then it disappears twice a day, which is extraordinary,” says Hunter, sitting miles from any marsh in a north London pub, visibly refreshed after her return from her traditional family holiday, swimming, sailing and savouring the salt marshes of a location she asks me not to reveal, with her husband, Benedict Cumberbatch, and their three sons. “Salt marshes are the last wild places in the UK. These liminal intertidal spaces have often been associated with outcasts, people living on the fringes of society. How can we shift our perception to realising how much value they have on so many levels?” Hunter reimagines the story of an outcast – the biblical figure of Lot’s wife, who was turned into a pillar of salt for daring to look back at the homeland she was forced to flee – in a new performance installation, Salt of the Earth, which delivers an urgent plea to save salt marshes. Each square kilometre of which actually sequesters and stores far more carbon than the same area of forest, as well as providing natural flood defences and biodiverse sanctuaries for endangered species. Yet more than half of the planet’s salt marshes have already been degraded or destroyed. And more are lost every year to development, rising seas and, ironically, human-made flood defences. The ingredients of Salt of the Earth, which will premiere in a former salt warehouse in Venice to coincide with the 81st Venice International film festival, are certainly intriguing. The audience will enter a landscape of salt – tonnes of it. Here, a monologue is performed by Lot’s wife (played by Olwen Fouéré), whom Hunter gives a name, Erith, and new agency. Determined to bear witness to the marshes she loves, says Hunter, “she chooses to look, to stay, to pay attention, rather than to go, forget and move on. That’s the heart of the piece – the potential sacrifice in that act”. The monologue is written by novelist Megan Hunter (Sophie’s sister-in-law) and followed by an installation film and a choral climax composed by Isobel Waller-Bridge. The 45-minute installation asks “what is it to bear witness? To pay attention?” says Hunter. “That is absolutely vital in saving the environment. As the poet Mary Oliver said, ‘Attention is the beginning of devotion.’ Pay attention, connect and then there’s something you want to fight for.” Hunter’s attention to salt marshes is rooted in childhood holidays on the estuaries of the Isle of Wight, where six generations of her mother’s family were raised. When she visited Venice to explore the possibility of making an environmental piece, she was drawn to the part that most tourists overlook: the vast lagoon surrounding the ancient city. The lagoon is the largest wetland in the Mediterranean basin but more than three-quarters of the salt marsh has been destroyed over the past century, mostly due to development. The entire lagoon, including Venice, is increasingly imperilled by rising seas and growing storminess wrought by the climate crisis. Hunter, who is fluent in Italian (a legacy of studying languages at Oxford), was guided through the lagoon by Andrea D’Alpaos, a leading expert on the ecology of the Venetian salt marshes. “He took me out on this open-topped boat on a really cold January morning through the marshes. An hour-long journey. Along the way he fed me pieces of information about them, and the cumulative effect of those anecdotes and being in the marshes made the seemingly unremarkable tufts of grass – because it was January, there were no flowers in bloom – feel like the most precious, sacred ecosystem.” Hunter’s varied creative career, taking in experimental theatre, operatic productions and a French-language album, is increasingly environmentally infused – although she’s also currently developing an opera about 16 nuns executed during the French Revolution. She produced the film of Megan Hunter’s climate dystopian novel The End We Start From, starring Jodie Comer and Cumberbatch, which was released earlier this year. The challenge of the climate crisis, says Hunter, is that “the knowledge deficit model – the idea that, given the facts, we’ll act” isn’t reflected in reality. Hunter and her scientist collaborators on Salt of the Earth are desperate for artistic interventions to motivate action. We need stories, she argues, to help people connect to the natural world. We can consider remote scientific data – rising carbon emissions, rising global averages for heat or seas – all we like, but really we need to experience how the crisis reshapes human lives. “Good storytelling connects people and creates empathy,” she says. “It’s only when you engage in emotion that you can then move on to something active.” Do climate crisis fictions risk becoming po-faced because we’re hammering a particular message? “Po-faced hammering is definitely not going to help anyone, so I’m not going to advocate for that. I don’t think all art should engage with the climate crisis but I’m definitely advocating for the potential and power of storytelling to work alongside science to inspire action. It is a very powerful tool.” Sceptics may see grand installations in Venice as a carbon emissions-creating, middle-class indulgence. “Of course you interrogate the money put into it,” says Hunter of the project. “The question has been asked: ‘Why wouldn’t you just put that into salt marsh restoration?’ But the scientists are saying, ‘We need you to be the mouthpiece, to move people to have that connection.’” Hunter says she is “constantly interrogating” the emissions question, offsetting but also trying to be “as carbon negative as possible”. The salt will be recycled; the costumes are “archival”. “I’ve gone through, interrogating greenwashing, and this is not that,” she says firmly. Critiquing artistic pleas to save salt marshes as the latest luvvie crusade (after rainforests, saving the whales etc) is simply a waste of energy, argues Hunter. “I acknowledge privilege but it’s bigger than that. I’ll take a platform and use it if it’s actually going to make a difference. If salt marshes are acknowledged as they hopefully will be, there will be tangible results and effects on people’s livelihoods.” Hunter hopes tangible results will come from the performance’s partnership with local activists in Venice, including We Are Here Venice, which delivers education about the importance of the salt marsh, and The Tidal Garden, a research collective working with chefs, scientists and farmers to develop new ways of producing salt marsh-friendly food within the lagoon. “We came to this piece very much with the criteria in mind of ‘What are we doing for the community in making it?’” says Hunter; the performance is even funding a salt marsh PhD at the University of Padova. Although it is performed for just three days, Hunter plans a global tour of the installation to places close to salt marshes around the world, including Britain, and connecting with other local charities. As Salt of the Earth puts heroines centre-stage in changing our relationship with the overlooked salt marsh, so Hunter has been particularly inspired by female scientists and environmentalists: Rachel Carson, the author of the groundbreaking Silent Spring; American marine biologist Sylvia Earle; and South American Indigenous activist Nemonte Nenquimo, whose book she is now reading. Clearly her experience as a mother has been formative as well. One of Hunter’s next projects is a TV series about the life of Margaret Wise Brown, the American author of the children’s classics Goodnight Moon and The Runaway Bunny, which Hunter read to her boys. Wise Brown was a radical member of the “here and now” movement in children’s literature and education, which put a prescient focus on seeking wonder in the everyday and “taking your cue from children rather than imposing this whole structure upon them” as Hunter puts it. “There’s a sharp contrast between what we’re dealing with today – the crisis of childhood, the atomisation and disconnectedness and everything that’s coming out about social media and young children – and this urgent message from the 1940s and 50s of connection with your child, connection with each other.” Hunter often returns to Carson, who once wrote that if she could give every newborn one gift it would be “a sense of wonder so indestructible that it would last throughout life”. Ultimately, Hunter wants to create works that help people to rediscover the natural world, an act that is intrinsically wonderful and optimistic. “This idea of engaging in connection with the natural world from the beginning,” she says: “that’s our hope.” Salt of the Earth premieres in Venice on 6 September